Gun barrel



FIG. 1 is a top, right side perspective view showing our new design;

FIG. 2 is a right side view thereof;

FIG. 3 is a left side view thereof;

FIG. 4 is a rear view thereof;

FIG. 5 is a front view thereof;

FIG. 6 is a top view thereof;

FIG. 7 is a bottom view thereof; and,

FIG. 8 is a bottom, right side perspective view thereof. 

The ornamental design for a gun barrel, as shown and described. 